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R_{out}/R_{sid} and Opacity at RHIC

Larry McLerran·Sandra S. Padula
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Abstract

One of the most dramatic results from the first RHIC run are the STAR results for pi+- pi+- interferometry. They showed that the ratio of the so-called R_{out} and R_{sid} radii seem to decrease below unity for increasing transverse momentum of the pair (K_T). This was subsequently confirmed by PHENIX, which also extended the K_T range of the measurements. We consider here the effects of opacity of the nuclei on this ratio, and find that such a small value is consistent with surface emission from an opaque source.

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Larry McLerran, Sandra S. Padula. 2002-11-18. R_{out}/R_{sid} and Opacity at RHIC. https://arxiv.org/abs/nucl-th/0205028

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